After injury to an ankle, such as a fracture or severe ankle sprain, it may be necessary to completely immobilize the ankle through the use of a molded plaster or resin cast. However, once the injury has been stabilized, recovery may be hastened by removing the molded plaster or resin cast and using a removable functional walking brace so that the ankle can be exercised during healing.
An important element of these functional walking braces is the liner element that provides a resilient support against the sides of the ankle. The liner helps stabilize the ankle against inversion and eversion while still permitting the normal dorsi-flexion and plantarflexion movement of the ankle. It has previously been proposed to form such pads of foam rubber, or using inflatable bags.
One such proposed prior ankle brace using an air-inflatable liner is shown in prior U.S. Pat. No. 4,280,489 listing Glen W. Johnson, Jr. as the inventor. Although the air-inflatable liner provides some resilient support against the ankle, it suffers from the following disadvantages. One disadvantage is that the air is unduly buoyant, and permits rapid movement of the air from one side to another, so that adequate support is not provided. Further, with air inflatable bladders, a puncture renders the braces inoperative and dangerous to the user as the outer rigid plastic shells could cut or rub the wearer.
The use of foam rubber pad, as a liner in walking braces is disclosed in U.S. Pat. No. 4,572,169 listing Maullin and Jones as inventors. The use of foam rubber has significant disadvantages in that the foam rubber is U.V. sensitive, and tends to deteriorate after a certain period of time. In addition, the open cells in the foam material collect moisture, such as sweat, with the undesired bacterial growth and odor. No such result can occur with gel pads. Further, the foam does not tend to conform to the configuration of the ankle joint, but bounces back to its original configuration. Also, neither air filled cushioning arrangements nor foam are suitable for hot and cold temperature therapy.
Accordingly, the objects of this invention include providing a walking brace liner that provides a resilient support against the ankle that is free from adverse effects of puncturing, lasts long and does not deteriorate in U.V. light, forms a relatively stable pad, conforms to the configuration of the ankle, has a high thermal capacity, has well defined boundaries, has homogeneous thickness throughout its length and width, and is very comfortable when used for therapeutic heating or chilling of the injured leg.